This invention relates to methods and apparatus for manufacturing composites combining thermoplastic polymers and rigid sheet metal, in particular, for fabricating rigid flat-rolled mild steel can components; and, more specifically, is concerned with combining selected polymeric formulations which facilitate fabricating pre-coated mild steel substrate into one-piece rigid can bodies, including beverage can bodies having what is referred to as ironed side walls.
An important object involves analyzing established practices which have limited polymeric coating of the interior of a one-piece drawn and ironed beverage can body to processes which are carried out after fabricating of that can body.
A related object is to enable combining polymers and flat-rolled mild steel to improve manufacturing, fabricating, and content shelf-life when using rigid one-piece can components for canning comestibles; and, in particular, improving shelf-life when using ironed-sidewall can bodies for canning acidified contents, including carbonated beverages, fruit juices, tea, and the like.
Further objects include embodiments with differing polymeric coating formulations and pre-coating method embodiments for combining with flat-rolled mild-steel substrate, so as to enable:
(i) increased manufacture of composite work-product, and
(ii) safer fabricating of can components utilizing those composite work-products.
A specific object is to enable polymeric pre-coating of a single-surface of corrosion-protected flat-rolled mild steel so as:
(i) to enhance can component fabrication, and
(ii) to increase shelf-life of cans utilizing rigid flat-rolled steel one-piece can bodies, including cans utilizing ironed-sidewall rigid one-piece can bodies.
A related object is enabling fabrication of polymeric pre-coated flat-rolled mild steel one-piece rigid can bodies, free of a requirement for post-fabricating polymer coating, or post-fabricating polymer coating repair.
Other objects and contributions are considered during the following more detailed description of the invention.